Predictors of occupational sensitisation to grain dust allergens and changes in lung function among grain mill workers in Cape Town

Occupationally-related airway diseases, including asthma and chronic obstructive lung disease, have emerged as having substantial public health importance. The aim of this study was to identify the predictors of occupational sensitisation to grain dust allergens and changes in lung function among grain mill workers in Cape Town. There were two major objectives of the study. Firstly, to determine which of the following factors determine the distribution of serum ECP (eosinophilic cationic protein): age, gender, grain dust exposure, smoking status, atopy and sensitisation to workplace allergens. Secondly, to investigate the risk factors associated with the following outcomes: i) sensitisation to occupational allergens; ii) diagnosis of occupational asthma; iii) diagnosis of chronic obstructive airways disease; and iv) longitudinal changes in lung function. The risk factors studied included age, gender, smoking habits, occupational exposure, lung function status on baseline survey (1989), and allergic sensitisation assessed at follow up (1996). The methods employed involved a repeat measures cross-sectional design including a cohort followed up at different points over a seven year period. Survey instruments included a questionnaire, spirometry and allergy tests (phadiotop, RAST for wheat, rye, Lepidoglyphus destructor, Tyrophagus putrescentiae and Sitophilus granarius). The results indicated an association of grain dust with pulmonary function and allergic sensitisation to grain dust constituents. After adjusting for known confounders such as age, gender and smoking, significant associations were found between employment duration and both decrements in lung function and sensitisation to wheat grain. A decrement of 278 ml in FEY 1 and 328 ml in FYC was associated with occupational sensitisation to wheat (and rye). Increasing employment duration resulted in annual decrements of 18.3 ml in FEY1 and 23 ml in FYC for every year employed. The odds for developing occupational asthma was only mildly elevated (OR=l.35) with increasing employment duration. Age, however, was found to be protective (OR=0.85). Although we were unable to demonstrate a relationship between across-week changes in lung function, at inception, and rapid longitudinal lung function decline, our findings suggested that longitudinal change was related to the degree of airway obstruction at inception. Sensitisation to grain dust allergens was also found to be an independent predictor for FEY 1 and FYC. The prevalence of sensitisation was the highest for wheat (26.4%), followed by Tyrophagus putrescentiae (22.6%), rye (21.7%), Lepidoglyphus destructor (15.1 %) and Sitophilus granarius (15.1 %). Sensitisation to wheat was highly correlated with sensitisation to rye (r = 0.92) and so were Lepidoglyphus destructor and Tyrophagus putrescentiae (r = 0.85). Although a large proportion of the workforce ( 41.5 % ) were sensitised to occupational allergens, the prevalence of respiratory symptoms was between 15.6% and 23.9%. There were 16.7% of workers with health outcomes which fulfilled our criteria for occupational asthma. Atopic workers in our study had at least a nine-fold increased odds of becoming sensitised to grain dust allergens (OR: 8.9-74.7) and a two-fold increased odds of developing occupational asthma (OR= 1.9-84.9). Furthermore, the study found that smokers had a twofold increased odds of becoming atopic, thereby placing them at greater risk of developing respiratory health problems. The mean ECP in this population was 15.4 ug/1 (SD:2.5). Although 45.3% of the workers were atopic, it was not found to be predictor of elevated ECP levels. We were however able to demonstrate a significant association between ECP and sensitisation to grain allergens. Workers sensitised to wheat (positive RAST) had, on average, 1. 78 ug/1 higher ECP levels. The odds of having an elevated ECP (> 15 ug/1) increased by 2.9 for workers sensitised to wheat grain. In conclusion, the results of the study indicate that selection effects are in operation, demonstrating the health worker effect. The findings also suggest that across week reactions may be less sensitive than the across shift changes in predicting rapid longitudinal decline in lung function. While we were able to characterise the distribution of ECP according to exposure, we were however unable to define the temporal relationship between elevated between exposures, ECP and lung function outcomes due to limitations of the study design

Health-Related Quality of Life (HRQoL) of Residents with Persistent Lower Respiratory Symptoms or Asthma Following a Sulphur Stockpile Fire Incident

Background: This study evaluated health-related quality of life (HRQoL) in residents with persistent lower respiratory symptoms (PLRS) or asthma six years after exposure to sulphur dioxide vapours emanating from an ignited sulphur stockpile. Methods:A cross-sectional study was carried out, using interview data collected at three time points (prior to, one- and six-years post incident), medical history, respiratory symptoms and HRQOL using the Medical Outcomes Study Form 36 (SF-36). Results: A total of 246 records, 74 with and 172 without PLRS or asthma, were analysed. The mean age was 42 (SD:12) years in the symptomatic group and 41 (SD:13) years in the asymptomatic group. Mean SF-36 scores were significantly lower for the symptomatic group in the Physical Functioning (24 vs. 39), Role—Physical (33 vs. 48) and General Health (GH) domains (24 vs. 37). Symptomatic residents experienced a significant decline in their Role—Physical (OR = 1.97; CI 1.09, 3.55) and GH (OR = 3.50; CI 1.39, 8.79) at year 6 compared to asymptomatic participants. Residents with co-morbid reactive upper airways dysfunction syndrome demonstrated stronger associations for GH (OR = 7.04; CI 1.61, 30.7) at year 1 and at year 6 (OR = 8.58; CI 1.10, 65.02). Conclusions:This study highlights the long-term adverse impact on HRQoL among residents with PLRS or asthma following a sulphur stockpile fire disaster

Occupational allergy associated with saltwater bony fish processing in South Africa.

The South African seafood industry employs over 28,000 mainly seasonal women workers involved predominantly in bony fish processing activities. The aim of this study was to determine the risk of developing work-related asthma and dermatitis during fish processing. A cross-sectional study of 594 workers in two factories involved in fish canning (pilchard) and fishmeal processing (anchovy and pilchard) was undertaken. All workers were evaluated using interviewer-administered questionnaires, skin prick tests with common airborne and fish allergen extracts, and pulmonary function including methacholine challenge tests. A subgroup of workers (n = 241) underwent skin examination and patch tests. Time-integrated environmental sampling using a thoracic fraction sampler collected 198 personal samples for total particulate mass, protein and specific fish antigen determinations. A novel ELISA-inhibition assay using polyclonal antibodies was developed for this purpose. Multivariate logistic and Cox proportional hazards models were used in the data analysis. Results of environmental samples demonstrated a wide variation in mean (arithmetic) airborne concentrations of thoracic particulate 0.61 mg/m 3 (0--11.3), total protein 0.89 mug/m3 (0--11.5), pilchard antigen 150 ng/m3 (0--15,973) and anchovy antigen 552 ng/m3 (0--75,748) levels. All four exposure metrics were consistently elevated for fishmeal production. Ambient pilchard and anchovy antigen levels were more strongly correlated with each other than total thoracic particulate and fish antigen concentrations. Common work-related symptoms reported included ocular-nasal (26%), asthma (16%) and skin symptoms (14%). The prevalence of atopy (positive skin prick test to one or more common allergens) was 36% with 7% sensitized to fish and 26% having nonspecific bronchial hyperresponsiveness. The prevalence of fish-related rhinoconjunctivitis was slightly higher (2.6%) than probable occupational asthma (1.8%), protein contact dermatitis and urticaria (Type I allergy) (1--2%), and allergic contact dermatitis due to fish (Type IV allergy) (1--3%). Atopy and smoking were important host factors related to fish sensitization. Workers with recurrent skin symptoms were twice as likely to be sensitized to fish. In Cox proportional hazards models, having work-related asthma symptoms was associated with a two-fold increased odds of being exposed to pilchard antigen concentrations >30 ng/m3 at the time when symptoms occurred. In conclusion, workers involved in bony fish processing (canning and fishmeal production) are at increased risk of developing work-related asthma symptoms due to inhalation of aerosols containing fish allergens.Ph.D.Health and Environmental SciencesImmunologyOccupational safetyPublic healthUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/123995/2/3106356.pd

Work-related allergic respiratory disease and asthma in spice mill workers is associated with inhalant chili pepper and garlic exposures

Objective The aim of the study was to determine the prevalence and risk factors for allergic respiratory disease in spice mill workers.\ud \ud Methods A cross-sectional study of 150 workers used European Community Respiratory Health Survey questionnaires, Phadiatop, serum specific IgE (garlic, chili pepper), spirometry and fractional exhaled nitric oxide (FeNO). Personal air samples (n=62) collected from eight-hour shifts were analysed for inhalable particulate mass. Novel immunological assays quantified airborne garlic and chili pepper allergen concentrations.\ud \ud Results Mean dust particulate mass (geometric mean (GM)=2.06 mg/m³), chili pepper (GM=0.44 µg/m³) and garlic allergen (GM=0.24 µg/m³) were highest in blending and were highly correlated. Workers' mean age was 33 years, 71% were men, 46% current smokers and 45% atopic. Spice-dust-related asthma-like symptoms (17%) were common, as was garlic sensitisation (19%), with 13% being monosensitised and 6% cosensitised to chili pepper. Airflow reversibility and FeNO>50 ppb was present in 4% and 8% of workers respectively. Spice-dust-related ocular-nasal (OR 2.40, CI 1.09 to 5.27) and asthma-like (OR 4.15, CI 1.09 to 15.72) symptoms were strongly associated with airborne garlic in the highly exposed (>0.235 µg/m³) workers. Workers monosensitised to garlic were more likely to be exposed to higher airborne chili pepper (>0.92 µg/m³) (OR 11.52, CI 1.17 to 113.11) than garlic allergens (OR 5.08, CI 1.17 to 22.08) in this mill. Probable asthma was also more strongly associated with chili pepper than with garlic sensitisation.\ud \ud Conclusions Exposure to inhalable spice dust (GM >2.06 mg/m³) containing garlic (GM>0.24 µg/m³) and chili pepper (GM >0.44 µg/m³) allergens increase the risk of allergic respiratory disease and asthma

Exposures and Health Effects of Bioaerosols in Seafood Processing Workers - a Position Statement

Occupational hazards exist in the processing of seafood both in land-based facilities as well as on board vessels. Recent findings on occupational injury and respiratory health risks among seafood processing workers were presented and discussed at the IFISH5 conference. Particular emphasis was put on the challenges that im/migrant workers encounter, the greater risks onboard factory vessels, especially where processing machinery are retrofitted to older vessels not primarily designed for this purpose, and the difficulties in assessing and preventing bioaerosol exposures and associated respiratory health risks despite recent advances in characterising agents responsible for allergic and non-allergic reactions. Based on appraisal of existing knowledge in the published literature and new findings presented at the conference, recommendations for immediate actions as well as for future research have been proposed. Among these include the importance of improving extraction ventilation systems, optimising machinery performance, enclosure of bioaerosol sources, improved work organization, and making special efforts to identify and support the needs of im/migrant workers to ensure they also benefit from such improvements. There is a need for studies that incorporate longitudinal study designs, have improved exposure and diagnostic methods, and that address seafood processing in countries with high seafood processing activities such as Asia and those that involve im/migrant workers worldwide. The medical and scientific community has an important role to play in prevention but cannot do this in isolation and should cooperate closely with hygienists, engineers, and national and international agencies to obtain better health outcomes for workers in the seafood industry